The Extensible Markup Language (XML) is becoming the de facto standard for information representation and exchange over the Internet. Owing to its hierarchical (recursive) and self-describing syntax, XML is flexible enough to express a large variety of information. To retrieve useful information from XML, queries expressed in query language like XPath is used to specify some elements that suit a given criteria. An XPath expression is comprised of a sequence of location steps, each consisting of an axis, a node test, and possibly a predicate.
A problem in modern command and control situations is that much data is available from different sensors. Several sensor data sources also require that the user has knowledge about the specific sensor types to be able to interpret the data.To alleviate the working situation for a commander, we have designed and constructed a system that [...]
The work presented in this thesis is related to XML (Extensible Markup Language) developed by World Wide Web Consortium (W3C)1. XML has be-come a dominant standard in the Internet and majority of data being exchanged on the Web is encoded using it. The thesis presents a type system for a substantial fragment of XML query [...]